If only one young member of the family develops breast cancer, it does not mean that the young patient did not develop the disease as a result of a genetic mutation, nor is it certain that other blood relatives do not have the oncogenic mutation and will not be inherited. Whether and when a carrier of a mutation eventually develops the disease is determined by a combination of factors, with some carriers developing the disease at a young age, some at an older age, and some not developing it for life. According to foreign literature, many younger members of the family develop the disease earlier than the older ones, and the younger age of breast cancer patients often indicates a greater possibility of gene mutation, so other sisters or elders in the family should be more alert to the development of breast cancer.